Technical Field
The present invention relates to control of a heating device including a plurality of heating zones.
Related Art
Conventionally, in a reflow device that is used in soldering when an electronic component is mounted on a surface of a printed circuit board, in order to heat the printed circuit board with a predetermined temperature profile, the printed circuit board is conveyed through a plurality of series-connected heating zones having different temperatures using a conveyer. A temperature controller performs on/off control of a heater provided in each heating zone, thereby adjusting the temperature of each heating zone.
In the reflow device, generally the heaters and the temperature controllers of all the heating zones are simultaneously powered on to separately heat up the heating zones to different setting temperatures. Therefore, until the temperature of the heating zone having the higher setting temperature is stabilized, powers of other heating zones are wasted for the purpose of temperature control.
For example, Patent Document 1 discloses a technology for reducing a total current of the heaters during a heat-up process by shifting a heat-up starting time of the heater in each heating zone. In the technology, the temperature to which the heating zone can be heated up in a predetermined time is previously measured in each heater, and the heat-up starting time of each heater is set by the measured value.
Patent Document 1: Japanese Patent No. 2885047 (issued Apr. 19, 1999)